When welding together two members, such as a pair of pipe lengths, a pipe length and a fitting, two fittings, and the like, it is not uncommon for the confronting ends of the two members to be mismatched. The mismatch may be due to one or both of the members being out-of-round, or to differences in wall thicknesses, or to differences in inside and outside diameters. Most of these mismatches can be corrected, or at least minimized, if the welder knows the extent of the mismatch and where it occurs. Various types of instruments and gauges have been proposed to assist the welder in locating the mismatch. Typical of such gauges are those disclosed on pages 25-28 of The Dearman System and in Lycan Pat. Nos. 3,869,801 and 4,165,566.
Known gauges of the type referred to utilize relatively movable body members terminating at corresponding ends in feelers or legs that project beyond the body members and terminate in outwardly extending feet. The legs must be of such thickness as to pass through a relatively narrow gap provided between the two members that are to be welded together, and they also must be of such size as to enable the gauge to be rotated through about 90.degree. so as to enable the feet to span the gap and project beyond both sides thereof for engagement with the inner surfaces of the members that are to be welded together. Because of these requirements the legs of the gauges must be relatively narrow or thin. As a result, the legs or feet, or both, are prone to be damaged, thereby resulting in inaccuracies in the use of the gauges.
An object of the present invention is to provide a welder's gauge which has all the advantages of previously known gauges adapted for similar purposes, but which makes possible the repair or replacement of those parts of the gauge which are most likely to become damaged, thereby avoiding the necessity of replacing an entire gauge upon one or both of its feelers being damaged.